[bigandy]

Hello, Sorry that my first post is a request for help.

I bought my 335i a couple of weeks ago thanks to all the guidance and information on this site. The only issue I have with it is an intermittent fault on the left rear light.

I get a warning come up on the i-drive screen regularly saying something along the lines of 'left hand side sidelight fault'. When I check the lights, the left hand brake light is dimly lit.

Does anybody have any ideas? I've tried swapping bulbs around and the fault stays with that brake light.

Cheers
Andy

[idnan]

Have you checked the contacts on the bulb holder in the rear light? They are prone to corrosion whch would give a bulb error and poor conductivity as a result may cause it to be dim.

[bigandy]

Hi Idnan,

Thanks for the reply. Yes I've checked them all and given them a rub with sand paper - wouldn't that cause the bulb to light up dimly when I touch the brake, not all the time? All other bulbs light up to the normal brightness and function correctly.

[sheps]

I had my bulb carriers replaced under warranty within a year of taking delivery. It's a known fault.

[bigandy]

Ok cheers Sheps. I'd heard about issues with the bulb carriers but I thought it was bulbs not lighting at all. I'll look in to that.

Cheers

[bigandy]

So, I've replaced the bulb holder and all new bulbs on that corner and I still have the same issue.

The issue seems to get worse/more frequent first thing in the morning or late in the evening.

A few seconds after touching the brake I get a 'sidelight fault' warning on the display and the left hand brake light illuminates dimly. After about 15 seconds the light goes off, until I next touch the brake, then the cycle repeats.

Does anyone have any more suggestion

Cheers, Andy

[bigandy]

Thought I'd update this as I've finally found the cause of this issue, 8 months later.

So, the root cause was an incorrect bulb fitted to the front lights (Angel Eyes), it was a H11 instead of the H8. It appears that the car would only detect a fault in cold or damp weather, and immediately after touching the brake, presumably that was enough to cause a slight spike in resistance and trigger the fault code. Any light failure seems to cause one of the brake light bulbs to light up dimly permanently, I guess so there's another warning for drivers that there's something wrong as they approach the car.

Hopefully this'll help someone else down the line...